From: Will Deacon <will@kernel.org>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64/mm: Avoid direct referencing page table enties in map_range()
Date: Thu, 1 Aug 2024 12:34:41 +0100 [thread overview]
Message-ID: <20240801113440.GB4476@willie-the-truck> (raw)
In-Reply-To: <3e82687a-0183-42f3-b32c-6d99dbd4fe49@arm.com>
On Thu, Jul 25, 2024 at 11:36:56AM +0100, Ryan Roberts wrote:
> On 25/07/2024 10:10, Anshuman Khandual wrote:
> > Like else where in arm64 platform, use WRITE_ONCE() in map_range() while
> > creating page table entries. This avoids referencing page table entries
> > directly.
>
> I could be wrong, but I don't think this code is ever operating on live
> pgtables? So there is never a potential to race with the HW walker and therefore
> no need to guarrantee copy atomicity? As long as the correct barriers are placed
> at the point where you load the pgdir into the TTBRx there should be no problem?
>
> If my assertion is correct, I don't think there is any need for this change.
Agreed.
Will
next prev parent reply other threads:[~2024-08-01 11:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-25 9:10 [PATCH] arm64/mm: Avoid direct referencing page table enties in map_range() Anshuman Khandual
2024-07-25 10:36 ` Ryan Roberts
2024-07-26 11:26 ` Anshuman Khandual
2024-08-01 11:34 ` Will Deacon [this message]
2024-08-01 12:48 ` Ryan Roberts
2024-08-01 13:23 ` Will Deacon
2024-08-01 14:07 ` Ryan Roberts
2024-08-01 14:46 ` Will Deacon
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